Scene of the park shooting

Meanwhile, a woman who raised concerns to a protective Services Officer about a man's behaviour at Parliament House six hours before the same man assaulted Mr Vongvixay made contact with police this afternoon.

"Homicide Squad detectives are continuing to appeal for any other witnesses as the investigation surrounding the assault and the subsequent death of the man in East Melbourne continues," Victoria Police spokeswoman Kelly Yates said.

The woman was urged to come forward after alerting a PSO at Parliament House to a man's "peculiar" behaviour.

"We believe she holds some information that could explain something of why this happened," Det-Insp John Potter said earlier.

The attacker's body near Fitzroy Gardens last night. The Herald Sun has obscured the man's image.

A PSO spoke to the man, who was known to police. The man left the scene.

But he returned six hours later, asking a different PSO for directions before bashing him over the head with a hammer and stealing his semi-automatic .40 calibre gun.

He was found dead six minutes later in Jolimont Reserve - 400m from the MCG.

Pedestrian Matthew Aldous has captured the chaotic scene of the Fitzroy Gardens shooting in Melbourne

"We are making an appeal today for information that could help us in tracing some background or cause factors to this incident," he said.

"We know at about 2.30pm yesterday afternoon the same man, who is now deceased, was spoken to by a different PSO at Parliament House.

"This man had by all accounts been behaving in a peculiar manner in the vicinity of Parliament House and a woman who saw this behaviour has approached the PSO and told him of her concerns about this man.

"The man has been spoken to by the PSO and since left the area but returned later that night about 8.30pm and assaulted a different PSO on duty."

An officer from the PSO has been assaulted and his alleged assailant is believed to have shot himself.

Neighbour Will Kelly said he also heard what he thought was a fire cracker before dozens of heavily-armed police flooded the street.

James, aged in his 40s, underwent a "successful" operation overnight in the Royal Melbourne Hospital for a fractured skull. He remains in a serious but stable condition and is expected to speak with family members today.

Detectives may release a picture of the offender "if there is a need" in a bid to locate witnesses who may have seen the man earlier in the day.

The 2.30pm confrontation was captured on CCTV but the incident at 8.30pm was not, police said.

Scene of the shooting

Assistant Commissioner Andrew Crisp said police, who returned to the scene about 8.50am to comb the area for clues, are now examining what could have prompted such a violent incident.

"Whether it was planned, or an opportunistic attack, that's a matter for the investigators at this point in time as they try to piece together what's happened prior to the incident, at the time of the incident and then post."

Last night as Parliament sat, the Speaker advised all members to stay indoors until the armed assailant could be found as the search went on.

Dozens of people were enjoying the warm evening outside restaurants and bars along Spring and Bourke streets when the attack happened.

Police speak to a PSO officer outside the Royal Melbourne Hospital where a PSO officer is in emergency after he was attacked with a hammer outside Parliament house. Picture: Nicole Garmston

A witness ran up the steps of Parliament House to alert security.

A political staffer said there were disorganised scenes.

"I came across it about 5-10 minutes later," the staffer said.

"The PSO was lying on the ramp to the right-hand side of the building being treated by paramedics.

The Police Association says the attack on a Protective Services Officer might have been prevented if he was not working alone

"At first we were told that they didn't believe the man had taken his weapon, but they weren't sure because they hadn't moved him (the PSO) at that stage.

"MPs and staffers were milling around out on the steps.

"Then they realised that he probably had taken the weapon."

Earlier this morning, Victorian Police Association Secretary Greg Davies said there was "something wrong with the system" when a person could assault a PSO before committing suicide.

A hammer lies next to the steps of State Parliament with a PSO officer's hat in the background. Picture: Jon Hargest

"How can we have people with such serious mental health issues go and arm themselves with a claw hammer to get a firearm?" he said.

HOW IT UNFOLDED

- 8.30pm man attacks PSO with hammer outside Parliament House at the corner of Spring and Bourke streets, grabs gun- Parliament sitting, with MPs and Premier Ted Baillieu inside- Witnesses describe chaotic scenes - Claims front doors of Parliament are not locked down- Soon after, shot heard around Fitzroy Gardens, 400m from the MCG- Man's body found in gardens- The injured officer, in his 40s, taken to hospital- Mr Baillieu gives press conference, saying he's 'distressed, concerned, grateful it didn't have wider consequences'- Assistant Commissioner Andrew Crisp says at scene no review of PSOs carrying weapons until investigation is over- Officer has successful operation to treat serious head injuries- The attacker - believed to have "mental-health issues" is known to police

Armed PSOs patrol Parliament House, which they have guarded for 25 years, the justice and court complexes around the city, and major office buildings including 1 Treasury Place, where the Premier works, and 121 Exhibition St, which houses a number of government departments and ministerial offices.

News.com.au's Privacy Policy includes important information about our collection, use and disclosure of your personal information (including to provide you with targeted content and advertising based on your online activities). It explains that if you do not provide us with information we have requested from you, we may not be able to provide you with the goods and services you require. It also explains how you can access or seek correction of your personal information, how you can complain about a breach of the Australian Privacy Principles and how we will deal with a complaint of that nature.

Comments on this story

Slime Eyes of MElbourne Posted at 11:33 AM December 12, 2012

I think it is sad to say at this early stage they should not have guns. This poor man was attacked with a hammer and is in hospital. For all we know, the first blow could have knocked him unconscious. No training in the world can help that. I would be more concerned with the security confusion after the fact.

Mel Posted at 9:46 AM December 12, 2012

Good on you "Steven" - "not properly trained"... ?!? For what? Getting it on the head with a hammer? Sorry mate - but you have no idea obviously what happens when a blunt object hits your skull with some force. It disables you. Hence any training you may have had regarding protection of your weapon is rendered pretty useless.
Tragedy for everyone really, the PSO - the poor bugger who was in such a place that he killed himself. Christmas eh....

Rappy Posted at 9:05 AM December 12, 2012

my thoughts go out to the unfortunate PSO, however it is obvious from the chaos which followed that security procedures for these establishments is inadequate - this situation could have been far worse - what are the response procedures for an attack on our parliament? our systems and training need to be reviewed urgently

A NOTE ABOUT RELEVANT ADVERTISING: We collect information about the content (including ads) you use across this site and use it to make both advertising and content more relevant to you on our network and other sites.